n. The collection of bubbles caused in a liquid by fermentation or agitation; spume; foam.n. Any foamy matter, as the foam at the mouth or on the sides of an over-driven horse.n. Something comparable to froth, as being light, unsubstantial, or evanescent.To foam; give out spume, foam, or foam-like matter.To cause to foam, as beer; cause froth to rise on the top of.To emit or discharge as froth; hence, to vent or give expression to, as what is unsubstantial or worthless: sometimes with out.To cover with froth: as, “the horse froths his bit,”